Electrical conductor



Jan. 15,' 1935.

T. D. wARlNG Er AL 1,987,918

ELECTRICAL CONDUCTOR Filed Nov. 3, 1932 2 Sheets-Sheet l UTVUQT'IIBIS Dfw @Ting J. BoiTLg-bro ke- Eg da 'JAY/ml Jan. 15, 1935. "r, D'. wAlNG E1' AL ELECTRI CAL CONDUCTOR Filed Nov. 3, 1932 2 Sheets-Sheet 2 m um m m, u uw m H MS v v ,N1 M wwwmwwwwwwwwwwwv l,

3711161 fors TJ), mari-n3 Patented Jan. 15, 1935 UNITED STATES PATENT OFFICE ELECTRICAL CONDUCTOR Application 16Claims.

This invention relates to electrical conductors and more particularly to that type of conductor in which the conducting wire is encased in and insulated from a metallic sheath and our object is to provide a conductor of this character in which the inductive capacity between the wire and sheath has been reduced to a minimum without danger of electrical contact between these parts.

We attain our objects by providing an insulation formed by one or more strands of paper wound on the conducting wire. Each strand comprises a plurality of 'strips of paper loosely twisted to provide a maximum air 'space throughout the insulation without danger of electrical contact being established'between the wire and its sheath even when the conductor is bent around sharp corners. cases both ends of the insulation to exclude moisture therefrom. Each end of the conducting wire may extend through the cover or may be connected with a rubber covered terminal wire and these terminal wires together with a third terminal wire connected with the metallic sheath extend through the rst mentioned rubber cover. The latter is vulcanized on the terminal wires or to the rubber covers thereof to form water tight joints at these outlet points.

The constructions are hereinafter more fully described and are illustrated in the accompanying drawings in which Fig. 1 is a longitudinal section, partly broken away, of our conductor;

Fig. 2 a side elevation of a portion of the conductor which is broken away to show the inu terior parts;

Fig. 3 a side elevation of a strand showing the formation thereof;

Fig. 4 a cross section of the conductor;

Fig. 5 a longitudinal section, partly broken away;

Fig. 6 a `longitudinal section of one end of another modified form of conductor;

Fig. 'Iv a longitudinal section, on an enlarged scale, of one end of another modified form of conductor;

Fig. 8 a longitudinal section of one end of a double conductor;

Fig. 9 a cross section of the conducting wires and insulations shown in Fig. 8; and

Fig. 10 a longitudinal section of one end of a modified form of double conductor.

l is a conducting wire on which is wound an insulation 2 comprising one or more strands 2L of paper, each strand being formed of one or A rubber cover en- November 3, 1932, Serial No. 640,974 In Canada June 21, 1932 more strips 2b of paper loosely twisted as shown in Fig. 3. Preferably each strand 2l comprises three loosely twisted strips of paper 2b and four of such strands are stranded on the wire 1 with their convolutions closely arranged so that. substantially the entire surface of the wire is covered. 'I'his arrangement not only affords numerous air spaces throughout the strands and between adjacent strands but prevents the strands from shifting longitudinally on the wire which would result in the strands being bunched at one spot and the wire being bared at another spot. One or more nat strips 2c of paper may be helically wound on the strand or strands 2*l to form a cylindrical casing around the strands and thus provide definite interstices for air between the strands and the casing formed by the strips 2.

A metallic sheath 3 which may be formed of braided Wire is disposed on the casing formed by the strips 2". Between the sheath 3 and paper strips 2c may be interposed a textile braid 4 for the purpose of preventing the strips from unravelling.

A rubber cover 5 is applied over the metallic sheath 3 and this cover is provided with extensions 5 which extend over the ends of the insulation 2 to encase the latter and thus exclude moisture therefrom. To prevent any longitudinal displacement of the braided wire sheath 3 during the application of the rubber cover 5, a

textile winding 8 is applied to the sheath before applying the rubber cover.

Any suitable moisture proof terminal connections such as those shown in the drawings, may

be provided for the sheath 3 and the opposite ends of the wire 1. Rubber covered terminal wires may be connected with the opposite ends of the wire l and a third rubber covered terminal wire 7 may be connected with the metallic sheath 3 as shown in Fig. 1. All these terminal wires extend through the extensions 5 of the rubber cover 5 which extensions are vulcanized to the rubber covers of the terminal wires 6 and 7 to hermetically seal the ends of the cover and prevent any access of moisture to the ends of the paper insulation. This insulation is formed of dry, unimpregnated paper which has a lower inductive capacity than paper impregnated with water proong materials.

From this description it is obvious that the specific formation and arrangement of the insulation 2 will reduce the inductive capacity between the wire 1 and sheath 3 to a minimum and at the same time aiord ample linsulation between these vparts to prevent them fromcominginto contact with one another when the conductor is bent or curved on a smallradius.

It is to be distinctly understood that the term conducting wire used throughout the specification and claims means either a,V single solid Wire, a braided conductor, or a plurality of stranded wires forming a stranded conductor.

Referring to the modification shown in Fig. 5, it will be noted that the rubber cover is encased, throughout its length between the sleeves 5", in a textile weatherproof casing 9, that the opposite ends of4 the conducting wire 1 extend through the sleeves 5b and that an uncovered terminal 7 isconnected with the sheath 3. The sleeves are vulcanized on the wires and tothe casing 9 and cover 5 to seal` the ends of the latter. In preparing the ends of the conductor to receive the sleeves 5b which in this case are separate from the rubber cover 5, the insulation 2, metallic sheath v3,v textile winding 8, cover 5 and textile casing 9 are made shorter than the-wire 1 or cut back from the ends thereof so that the wire will extend through the sleeves 5b and-beyond the outer endsv thereof.' Further, the winding 8, cover 5 and casing 9 are so cut away adjacent each end of the conductor that portions of t'he metallic sheath 3 and the cover 5 are temporarily uncovered. These uncovered portions are then encased by the sleeves, each sleeve 5P being vulcanized to the cover 5 and to the end portion of better but 'will bend therewith and thus prevent openings being formed at the `junctures of the wires and sleeves. The terminal wire '7 corresponds to the hereinbefore described wire '7 and differs from the latter in that one is rubberv covered and the other is bare.

In Fig. 6, the cover 5d is applied to the casing 2 of the insulation 2 and the metallic sheath 3d is interposed between the cover 5d and the casing 9. To prevent any longitudinal displacement of the casing 2 during the application of the rubber cover 5, a textile winding 8d is applied to the casing 2 before applying the rubber cover. In this case, the ends of the sheathd and casing 9 are so cutrelative to one anothenthat the sleeves 5e may be .vulcanized to the cover 5d and casing 9 while in contact with the ends of the sheath 3d and wires 1 and 7. The cover and sleeves thus hermetically seal the ends of the paper insulation 2, and the sleeves seal the ends of the sheath 3 and casing 9 while the latter Fig. 'l isl an enlarged detail of the left hand end of the conductor shown in Fig. 5 and differs therefrom in that a terminal wire 7b is connected with the left hand end Aof the sheath 3 and that the Wires '7h .and '1 are formed of stranded and Vbraided wires respectively. To prevent moisture from reaching the insulation through the inter- 'stices in either of these types of wires, we fill the intcrstices with solder or. the like, as indi- 1,9s7,91s v Acated at 7 and 1b, to make the wires solid for portions of their lengths between the ends of the insulation 2 and the ends of the sleeve projections 5. It is to be understood that the right hand end of the portion of the conductor in Fig. 7 may correspond to the left hand end shown therein and that in this case both ends of the slbieath 3 may be provided with terminal wires -7 For 'certain purposes, it is required to employ a plurality of shielded conducting wires 1 in addition to the terminal wires 7 or '7b at opposite ends of the sheath 3 or 3. Referring to Figs. 8, 9 and 10, two ,conducting vwires 1 with their insulations 2 are twisted or stranded around one another'to form the core of this conductor. 'Ihat is to say, on each wire 1 is `iwound the hereinbefore described strand or strands 2 of paper on which strand or strands are fhelically wound the flat -strip or strips 2 of paper to form a substantially cylindrical casing around the strands. 'I'hese cylindrical casings 2 are then twisted or stranded on one another and are covered by a paper wrapping 2d which may be formed of one or more fiat strips of paper helically wound round the stranded casings 2.' As a means tending to overcome any tendency of the casings 2 from closely following the contours of one another while being stranded on one another and thus tending to close the interstices for air between the convolutions of the strands 2 and between the latter and the casings 2, the strand or strands 2 on one wire 1 may be wound in one direction of rotation (see Fig. 2) and the strand or strands 2a on the other wire 1 will be wound in the other direction of rotation. If it be desired to make the cross sectional contour of the wrapping 2d circular throughout its length, llers 2 could be stranded with the casings 2 to round out the latter while the wrapping 2d is applied thereto. These llers may be formed similar to the strands 2.v

In Fig. 8, the metallic sheath 3 is disposed on the wrapping 2d and the winding 8, cover 5, textile weatherproof casing 9 and sleeves 51 are applied as shown in Fig. 5 and hereinbefore described.

In Fig. 10, the cover 5d is disposed on the wrapping 2d and the metallic sheath 3, winding 8, textile weatherproof casing 9 and sleeves 5 are applied as shown in Fig. 6 and hereinbefore described.

It will be noted that in all cases the construction of the insulation is substantially the same and that the rubber cover 5 or 5a is provided with extensions 5a or with sleeves 5b or 5 forming extensions of the cover to hermetically seal the ends of the paper insulation 2. When the textile winding 8 or 8d is used, it will be noted that it is always interposed between the rubber cover 5 or 5fl and the part of the conductor it is desired to cover so that the cover may be applied by an extruding machine without danger of the said-part being displaced longitudinally as it is drawn through the dies.

vWhat we claim as our invention is:

1. An electrical conductor comprising a conducting wire; an insulation comprising a strip of paper twisted into a strand wound on the wire; a metallic sheath; and a rubber cover, the sheath. andcover encasing the insulation, the cover encasing both ends of the paper insulation.

2.v An electrical conductor comprising a conducting wire; a flexible insulation having a low inductive capacity applied to the wire; a metallic sheath; a rubber cover, the sheath and cover encasing the insulation, the cover encasing both ends of the insulation; and three rubber covered terminal wires, one being connected with .each end of the conducting wire and one with the metallic sheath, the terminal wires extending through the iirst mentioned cover and the latter being vulcanized to therubber covers of the terminal wires.

3. An electrical conductor comprising a conducting wire; an insulation comprising a plurality of strips of paper twisted into a strand wound on the wire; a metallic sheath; and a rubber cover, the sheath and cover encasing the insulation, the cover encasing both ends of the paper insulation.

4. An electrical conductor comprising a conducting wire; an insulation comprising a plurality of strands of paper stranded on the wire, each strand comprising a strip of paper loosely twisted; a metallic sheath; and a rubber cover, the sheath and cover encasing the insulation,

lthe cover encasing both ends of the paper inducting wire; an insulation comprising a strip of paper twisted into a strand wound on the wire; a ilat strip of paper helically wound on the strand of paper; a metallic sheath; and a rubber cover, the sheath and cover encasing the insulation, the cover encasing both ends of the paper insulation.

7. An electrical conductor comprising a conducting wire; an insulation comprising a strip of paper twisted into a strand wound closely on the wire to substantially cover the entire surface thereof; a metallic sheath; and a rubber cover, the sheath and cover encasing the insulation, the cover encasing both ends of the paper insulation. e

8. An electrical conductor comprising a conducting wire; an insulation comprising a plurality of strips of paper twisted into a strand wound closely on the wire to substantially cover the entire-surface thereof; a metallic sheath; and a rubber cover, the sheath and cover encasing the insulation, the cover encasing both ends of the paper insulation.

9. An electrical conductor comprising a conducting wire; an insulation comprising a plurality of strands of paper stranded on the wire, the strands being adapted to substantially surround the entire surface ofthe wire and each strand comprising a plurality of strips of paper loosely twisted; a metallic sheath; and a rub-l ber cover, the sheath and coyer encasing the instrand comprising a plurality of strips of paper loosely twisted; a metallic sheath; and a rubber cover, the sheath and cover encasing the insulation,vthe cover encasing both ends of the paper insulation; and three rubber covered terminal wires, one being connected with each end of the conducting wire and one with the metallic sheath, the terminal wires extending through the iirst mentioned cover and the latter being vulcanized to the rubber covers of the terminal wires.

1 11. An electrical conductor comprising a conducting wire; an insulation comprising a plurality of strands of paper stranded on the wire, each strand comprising a plurality of strips of paper loosely twisted; a metallic sheath; a rubber cover, the sheath and cover encasing the insulation, the cover encasing both ends of the paper insulation; and terminal wires leading from the metallic sheath and each end of the conducting wire through the cover, the latter having a moisture proof connection with the wires.

- 12. An electrical conductor comprising a conducting wire; an insulation comprising a plurality of strands of paper stranded on the wire, each strand comprising a plurality of strips of paper loosely twisted; a fiat strip of paper helically wound on the strand of paper; a textile braid disposed on the insulation; a metallic braid disposed on the textile braid; and a rubber cover encasing `the metallic braid and both ends of the paper insulation. f

13. An electrical conductor comprising a conducting wire; an insulation comprising a strip of paper twisted into a strand wound on the wire; a metallic braid disposed on the insulation; a textile winding disposed on the metallic braid; .and a rubber cover encasing the textile winding and both ends of the paper insulation.

14. An electrical conductor comprising a conducting wire; an insulation comprising a plurality of strands oi.' paper stranded on the wire, each strand comprising a plurality of strips of paper loosely twisted; a iiat strip of paper helically wound on the strand of paper; a textile braid disposed on the insulation; a metallic braid disposed on the textile braid; a textile winding disposed on the metallic braid; and a rubber cover encasing the textile winding and both ends of the paper insulation.

15. An electrical conductor comprising a conducting wire; a dry insulation disposed on the wire; a metallic sheath; a rubber cover, the sheath and cover encasing the insulation; a textile casing encasing the sheath and cover, the conducting wire having its ends projecting beyond the ends of the insulation, sheath, cover, and casing, the ends of the cover projecting be- -yond the ends oi' the textile casing; a terminal Wire connected with the metallic sheath; and rubber sleeves surrounding the wires, the ends of the cover and the insulation and vulcanized to the cover to seal both ends of the insulation.

16. An electrical conductor constructed as set forth in claim l5 in which the outer ends of the sleeves are provided with tubular projections vulcanized on the wires, the said projections being smaller in diameter than the sleeves.

TRACY D. WARING. JOHN BOLINGBROKE. 

